This disclosure relates generally to pedestrian platforms, walkways and sidewalks and more particularly to pedestrian platforms, walkways and sidewalks for the blind and visually impaired. There is often the need, in public transit facilities, for pedestrians to detect the location of a public transportation platform or other pedestrian surface that may present a potential hazard. By making the pedestrian aware of a specific location a potential danger may be avoided. By way of example, this may include railroad crossings, subway platforms, loading docks, stages, stairways, sidewalks, curb ramps, crosswalks, man holes, potholes, and so on.
The Americans with Disabilities Act (ADA): “Accessibility Guidelines for Buildings and Facilities” sets the requirements for the use of detectable warnings at curb ramps, walking surfaces, transit platforms and the like to warn visually impaired people of hazards. The guidelines require that detectable warnings shall consist of truncated domes with a diameter nominal of 0.9″ (23 mm), a height nominal of 0.2″ (5 mm), a center-to-center spacing nominal of 2.35″ (60 mm), and shall contrast visually with adjoining surfaces, either light on dark or dark on light. The material used to provide contrast shall be an integral part of the walking surface. Detectable warnings used on interior surfaces are required to differ from adjoining surfaces in resiliency or sound-on-cane contact. Platform edges bordering a drop off and not protected by screens or guard rails shall have a detectable warning 24 inches wide running the full length of the platform drop off. If a walkway crosses or adjoins a vehicular way, and the walking surface is not separated by curbs, railing or other element between the pedestrian areas and the vehicular areas, the boundary between such area is to be identifiable by a continuous detectable warning 36 inches wide. Curb ramps are also required to have detectable warnings extending the full width and depth of the curb ramp.
Known within the art are tiles designed to be glued or mechanically fastened to an existing walking surface. U.S. Pat. No. 4,715,743 issued to Schmanski discloses a uniform adhesive layer applied to a tile, which is then adhered to a surface. Tiles installed according to this method are not meant to be flush with the ground and may come undone due to abrasion at their exposed edges. Also known within the art is the use of a patterned tool to produce a durable tactile warning surface for sidewalks and other walkways including pouring a concrete base, applying pigmented or colored hardener to the upper surface of the concrete base and stamping the upper surface of the base with a patterned tool. This can be relatively costly. Also, there is room for imperfections and errors.
Adherence of a tile to a walkway surface is a critical aspect of the present tiled surface requirement. Prior efforts to retain a tile in an attached position have been frustrated by separation of the peripheral edge of the tile from the pavement. Such separation can present a danger to the visually impaired rather than solve the intended problem in the first place. Prior attempts to solve this problem have included the stamping of concrete, and the use of plastic tiles with chamfered edges. However, as mentioned, stamping is costly, prone to errors, labor intensive and requires on site work. Some plastic materials that have been used for pedestrian tiles are fragile and subject to lifting from their base surface. Accordingly, what is needed is a textured tile system and method of installation that allows for pre-cast tiles to be easily installed, that are installed flush with the base surface, and that may be installed without significant labor, and that are in compliance with ADA requirements.